io.prestosql.sql.planner.iterative.rule

Class RemoveRedundantTopN

java.lang.Object

io.prestosql.sql.planner.iterative.rule.RemoveRedundantTopN

All Implemented Interfaces:

Rule<TopNNode>

public class RemoveRedundantTopN
extends Object
implements Rule<TopNNode>

Replace TopN node 1. With a Sort node when the subplan is guaranteed to produce fewer rows than N 2. With its source when the subplan produces only one row 3. With a empty ValuesNode when N is 0

Nested Class Summary

Nested classes/interfaces inherited from interface io.prestosql.sql.planner.iterative.Rule

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor and Description
RemoveRedundantTopN()

Method Summary

Modifier and Type	Method and Description
Rule.Result	apply(TopNNode node, Captures captures, Rule.Context context)
Pattern<TopNNode>	getPattern() Returns a pattern to which plan nodes this rule applies.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.prestosql.sql.planner.iterative.Rule

isEnabled

Constructor Detail

RemoveRedundantTopN

public RemoveRedundantTopN()

Method Detail

getPattern

public Pattern<TopNNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<TopNNode>

apply

public Rule.Result apply(TopNNode node,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<TopNNode>